Recent advances in fluorescence microcopy have revolutionized the ability to resolve images of biological structures. This revised proposal requests funding for the purchase of a confocal microscope imaging system, which will be shared by research laboratories form the Department of Biology and the Center for Neural Science at New York University. These investigators have extensive expertise in confocal imaging, but currently have little or no access to a state-of-the art instrument. NIH funded projects that currently use confocal imaging include: the detection and quantification of gene expression patterns in multicellular animals and plants, the visualization of individual nerve cells in brain slices, and the analysis of structural details within cells and contact points between cells. The specific aims of this proposal are to: 1) Determine the subcellular localization of multiple labeled biological structures in three- dimensions at high resolution. 2) Determine the localization and dynamic interactions between biological structures in living cells and organisms over time at high resolution. 3) Determine the localization of biological structures in thick samples and reconstruct the position of such structures using three-dimensional rendering methods. The requested CM system will complement existing imaging facilities within the Biology department and will bridge an important gap in technologies currently available for NIH-funded research projects. The university will provide support for the installation and maintenance of the facility, and a management structure to oversee faculty and student training, access, usage, and instrument upkeep.